Katsutoshi Matsuzaki is a Japanese entertainer born on September 2, 1983, in Fukuoka Prefecture, Japan. He is known for his blood type A and a height of 169 cm. While he has performed voice acting work, his career background is primarily rooted in comedy as a former member of the comedy duo Yasashii Ame (Gentle Rain), which he formed with Jun Yoshimoto in 2004 and which dissolved in 2020. His comedy often incorporated references to otaku culture, and after the duo ended, he continued his career as a solo comedian. Matsuzaki also authored a book titled I Love Characters So Much That Life Is Tough.

Within the anime industry, Matsuzaki is best known for his role as Masakazu Yamada in the 2013 television anime series Flowers of Evil (Aku no Hana). This series, which used rotoscoping animation, was based on the manga by Shūzō Oshimi. He was part of a supporting cast that included Shinichiro Ueda as the protagonist Takao Kasuga, and he participated in a talk event for the show in June 2013 alongside the director and other staff.

Besides his notable part in Flowers of Evil, his other anime-related appearances are not as a voice actor for fictional characters but rather as cameo appearances as himself in series such as Recently, My Sister Is Unusual and Blend S. Information regarding major recurring collaborative relationships with specific directors, studios, or production teams for voice acting work is not available.